1. Field of the Invention
The present invention relates to agents that bind sphingosine-1-phosphate (S1P), particularly to humanized monoclonal antibodies, antibody fragments, and antibody derivatives specifically reactive to S1P under physiological conditions. Such agents can be used in the treatment and/or prevention of various diseases or conditions through the delivery of pharmaceutical compositions that contain such agents.
The following description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein, or any publication specifically or implicitly referenced herein, is prior art, or even particularly relevant, to the presently claimed invention.
2. Background.
Bioactive Signaling Lipids
Lipids and their derivatives are now recognized as important targets for medical research, not as just simple structural elements in cell membranes or as a source of energy for β-oxidation, glycolysis or other metabolic processes. In particular, certain bioactive lipids function as signaling mediators important in animal and human disease. Although most of the lipids of the plasma membrane play an exclusively structural role, a small proportion of them are involved in relaying extracellular stimuli into cells. “Lipid signaling” refers to any of a number of cellular signal transduction pathways that use cell membrane lipids as second messengers, as well as referring to direct interaction of a lipid signaling molecule with its own specific receptor. Lipid signaling pathways are activated by a variety of extracellular stimuli, ranging from growth factors to inflammatory cytokines, and regulate cell fate decisions such as apoptosis, differentiation and proliferation. Research into bioactive lipid signaling is an area of intense scientific investigation as more and more bioactive lipids are identified and their actions characterized.
Examples of bioactive lipids include the eicosanoids (including the cannabinoids, leukotrienes, prostaglandins, lipoxins, epoxyeicosatrienoic acids, and isoeicosanoids), non-eicosanoid cannabinoid mediators, phospholipids and their derivatives such as phosphatidic acid (PA) and phosphatidylglycerol (PG), platelet activating factor (PAF) and cardiolipins as well as lysophospholipids such as lysophosphatidyl choline (LPC) and various lysophosphatidic acids (LPA). Bioactive signaling lipid mediators also include the sphingolipids such as sphingomyelin, ceramide, ceramide-1-phosphate, sphingosine, sphingosylphosphoryl choline, sphinganine, sphinganine-1-phosphate (Dihydro-S1P) and sphingosine-1-phosphate. Sphingolipids and their derivatives represent a group of extracellular and intracellular signaling molecules with pleiotropic effects on important cellular processes. Other examples of bioactive signaling lipids include phosphatidylserine (PS), phosphatidylinositol (PI), phosphatidylethanolamine (PEA), diacylglyceride (DG), sulfatides, gangliosides, and cerebrosides.
Sphingolipids are a unique class of lipids that were named, due to their initially mysterious nature, after the Sphinx Sphingolipids were initially characterized as primary structural components of cell membranes, but recent studies indicate that sphingolipids also serve as cellular signaling and regulatory molecules (Hannun, et al., Adv. Lipid Res. 25:27-41, 1993; Speigel, et al., FASEB J. 10:1388-1397, 1996; Igarashi, J. Biochem 122:1080-1087, 1997; Hla, T. (2004). Semin Cell Dev Biol, 15, 513-2; Gardell, S. E., Dubin, A. E. & Chun, J. (2006). Trends Mol Med, 12, 65-75). Sphingolipids are primary structural components of cell membranes that also serve as cellular signaling and regulatory molecules (Hannun and Bell, Adv. Lipid Res. 25: 27-41, 1993; Igarashi, J. Biochem 122: 1080-1087, 1997). The sphingolipid signaling mediators, ceramide (CER), sphingosine (SPH) and sphingosine-1-phosphate (S1P), have been most widely studied and have recently been appreciated for their roles in the cardiovascular system, angiogenesis and tumor biology (Claus, et al., Curr Drug Targets 1: 185-205, 2000; Levade, et al., Circ. Res. 89: 957-968, 2001; Wang, et al., J. Biol. Chem. 274: 35343-50, 1999; Wascholowski and Giannis, Drug News Perspect. 14: 581-90, 2001; Spiegel, S. & Milstien, S. (2003). Sphingosine-1-phosphate: an enigmatic signaling lipid. Nat Rev Mol Cell Biol, 4, 397-407).
For a review of sphingolipid metabolism, see Liu, et al., Crit. Rev. Clin. Lab. Sci. 36:511-573, 1999. For reviews of the sphingomyelin signaling pathway, see Hannun, et al., Adv. Lipid Res. 25:27-41, 1993; Liu, et al., Crit. Rev. Clin. Lab. Sci. 36:511-573, 1999; Igarashi, J. Biochem. 122:1080-1087, 1997; Oral, et al., J. Biol. Chem. 272:4836-4842, 1997; and Spiegel et al., Biochemistry (Moscow) 63:69-83, 1998.
S1P is a mediator of cell proliferation and protects from apoptosis through the activation of survival pathways (Maceyka, et al. (2002), BBA, vol. 1585): 192-201, and Spiegel, et al. (2003), Nature Reviews Molecular Cell Biology, vol. 4: 397-407). It has been proposed that the balance between CER/SPH levels and S1P provides a rheostat mechanism that decides whether a cell is directed into the death pathway or is protected from apoptosis. The key regulatory enzyme of the rheostat mechanism is sphingosine kinase (SPHK) whose role is to convert the death-promoting bioactive signaling lipids (CER/SPH) into the growth-promoting S1P. S1P has two fates: S1P can be degraded by S1P lyase, an enzyme that cleaves S1P to phosphoethanolamine and hexadecanal, or, less common, hydrolyzed by S1P phosphatase to SPH.
The pleiotropic biological activities of S1P are mediated via a family of G protein-coupled receptors (GPCRs) originally known as Endothelial Differentiation Genes (EDG). Five GPCRs have been identified as high-affinity S1P receptors (S1PRs): S1P1/EDG-1, S1P2/EDG-5, S1P3/EDG-3, S1P4/EDG-6, and S1PS/EDG-8 only identified as late as 1998 (Lee, et al., 1998). Many responses evoked by S1P are coupled to different heterotrimeric G proteins (Gq−, Gi, G12-13) and the small GTPases of the Rho family (Gardell, et al., 2006).
In the adult, S1P is released from platelets (Murata et al., 2000) and mast cells to create a local pulse of free S1P (sufficient enough to exceed the Kd of the S1PRs) for promoting wound healing and participating in the inflammatory response. Under normal conditions, the total S1P in the plasma is quite high (300-500 nM); however, it has been hypothesized that most of the S1P may be ‘buffered’ by serum proteins, particularly lipoproteins (e.g., HDL>LDL>VLDL) and albumin, so that the bio-available S1P (or the free fraction of S1P) is not sufficient to appreciably activate S1PRs (Murata et al., 2000). If this were not the case, inappropriate angiogenesis and inflammation would result. Intracellular actions of S1P have also been suggested (see, e.g., Spiegel S, Kolesnick R (2002), Leukemia, vol. 16: 1596-602; Suomalainen, et at (2005), Am J Pathol, vol. 166: 773-81).
Widespread expression of the cell surface S1P receptors allows S1P to influence a diverse spectrum of cellular responses, including proliferation, adhesion, contraction, motility, morphogenesis, differentiation, and survival. This spectrum of response appears to depend upon the overlapping or distinct expression patterns of the S1P receptors within the cell and tissue systems. In addition, crosstalk between S1P and growth factor signaling pathways, including platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), and basic fibroblastic growth factor (bFGF), have recently been demonstrated (see, e.g., Baudhuin, et al. (2004), FASEB J, vol. 18: 341-3). The regulation of various cellular processes involving S1P has particular impact on neuronal signaling, vascular tone, wound healing, immune cell trafficking, reproduction, and cardiovascular function, among others. Alterations of endogenous levels of S1P within these systems can have detrimental effects, eliciting several pathophysiological conditions, including cancer, inflammation, angiogenesis, heart disease, asthma, and autoimmune diseases.
A recent novel approach to the treatment of various diseases and disorders, including cardiovascular diseases, cerebrovascular diseases, and various cancers, involves reducing levels of biologically available S1P, either alone or in combination with other treatments. While sphingolipid-based treatment strategies that target key enzymes of the sphingolipid metabolic pathway, such as SPHK, have been proposed, interference with the lipid mediator S1P itself has not until recently been emphasized, largely because of difficulties in directly mitigating this lipid target, in particular because of the difficulty first in raising and then in detecting antibodies against the S1P target.
Recently, the generation of antibodies specific for S1P has been described. See, e.g., commonly owned, U.S. patent application Ser. No. 20070148168; WO2007/053447. Such antibodies, which can, for example, selectively adsorb S1P from serum, act as molecular sponges to neutralize extracellular S1P. See also commonly owned U.S. Pat. Nos. 6,881,546 and 6,858,383 and U.S. patent application Ser. No. 10/029,372. SPHINGOMAB™, the murine monoclonal antibody (mAb) developed by Lpath, Inc. and described in certain patents or patent applications listed above, has been shown to be effective in models of human disease. In some situations, a humanized antibody may be preferable to a murine antibody, particularly for therapeutic uses in humans, where human-anti-mouse antibody (HAMA) response may occur. Such a response may reduce the effectiveness of the antibody by neutralizing the binding activity and/or by rapidly clearing the antibody from circulation in the body. The HAMA response can also cause toxicities with subsequent administrations of mouse antibodies.
A humanized anti-S1P antibody has been developed by Lpath, Inc. This antibody has all the advantages of the murine mAb in terms of efficacy in binding S1P, neutralizing S1P and modulating disease states related to S1P, but with none of the potential disadvantages of the murine mAb when used in a human context. As described in the examples hereinbelow, this humanized antibody (referred to as LT1009 or sonepcizumab) has in fact shown activity greater than that of the parent (murine) antibody in animal models of disease.
3. Definitions
Before describing the instant invention in detail, several terms used in the context of the present invention will be defined. In addition to these terms, others are defined elsewhere in the specification, as necessary. Unless otherwise expressly defined herein, terms of art used in this specification will have their art-recognized meanings. In the event of conflict, the present specification, including definitions, will control.
An “immune-derived moiety” includes any antibody (Ab) or immunoglobulin (Ig), and refers to any form of a peptide, polypeptide derived from, modeled after or encoded by, an immunoglobulin gene, or a fragment of such peptide or polypeptide that is capable of binding an antigen or epitope (see, e.g., Immunobiology, 5th Edition, Janeway, Travers, Walport, Shlomchiked. (editors), Garland Publishing (2001)). In the present invention, the antigen is a bioactive lipid molecule.
An “anti-S1P antibody” or an “immune-derived moiety reactive against S1P” refers to any antibody or antibody-derived molecule that binds S1P. As will be understood from these definitions, antibodies or immune-derived moieties may be polyclonal or monoclonal and may be generated through a variety of means, and/or may be isolated from an animal, including a human subject.
A “bioactive lipid” refers to a lipid signaling molecule. In general, a bioactive lipid does not reside in a biological membrane when it exerts its signaling effects, which is to say that while such a lipid species may exist at some point in a biological membrane (for example, a cell membrane, a membrane of a cell organelle, etc.), when associated with a biological membrane it is not a “bioactive lipid” but is instead a “structural lipid” molecule. Bioactive lipids are distinguished from structural lipids (e.g., membrane-bound phospholipids) in that they mediate extracellular and/or intracellular signaling and thus are involved in controlling the function of many types of cells by modulating differentiation, migration, proliferation, secretion, survival, and other processes. In vivo, bioactive lipids can be found in extracellular fluids, where they can be complexed with other molecules, for example serum proteins such as albumin and lipoproteins, or in “free” form, i.e., not complexed with another molecule species. As extracellular mediators, some bioactive lipids alter cell signaling by activating membrane-bound ion channels or G-protein coupled receptors that, in turn, activate complex signaling systems that result in changes in cell function or survival. As intracellular mediators, bioactive lipids can exert their actions by directly interacting with intracellular components such as enzymes and ion channels. Representative examples of bioactive lipids include LPA and S1P.
The term “therapeutic agent” means an agent to mitigate angiogenesis and/or neovascularization, e.g., CNV and BV maturation, edema, vascular permeability and fibrosis, fibrogenesis and scarring associated with, or part of the underlying pathology of, ocular diseases and conditions.
The term “combination therapy” refers to a therapeutic regimen that involves the provision of at least two distinct therapies to achieve an indicated therapeutic effect. For example, a combination therapy may involve the administration of two or more chemically distinct active ingredients, for example, an anti-LPA antibody and an anti-S1P antibody. Alternatively, a combination therapy may involve the administration of an immune-derived moiety reactive against a bioactive lipid and the administration of one or more other medicaments, such as pain relief agents. Combination therapy may, alternatively, involve administration of an anti-lipid antibody together with the delivery of another treatment, such as radiation therapy and/or surgery. Further, a combination therapy may involve administration of an anti-lipid antibody together with one or more other biological agents (e.g., anti-VEGF, TGFβ, PDGF, or bFGF agent), other medicaments and another treatment such as radiation and/or surgery. In the context of combination therapy using two or more chemically distinct active ingredients, it is understood that the active ingredients may be administered as part of the same composition or as different compositions. When administered as separate compositions, the compositions comprising the different active ingredients may be administered at the same or different times, by the same or different routes, using the same of different dosing regimens, all as the particular context requires and as determined by the attending physician. Similarly, when one or more anti-lipid antibody species, for example, an anti-S1P antibody, alone or in conjunction with one or more medicaments are combined with, for example, radiation and/or surgery, the drug(s) may be delivered before or after surgery or radiation treatment.
An “anti-S1P agent” refers to any agent that is specifically reactive to S1P, and includes antibodies or antibody-derived molecules or non-antibody-derived moieties that bind S1P and its variants.
A “hapten” refers to a molecule adapted for conjugation to a hapten, thereby rendering the hapten immunogenic. A representative, non-limiting class of hapten molecules is proteins, examples of which include albumin, keyhole limpet hemocyanin, hemaglutanin, tetanus, and diphtheria toxoid. Other classes and examples of hapten molecules suitable for use in accordance with the invention are known in the art. These, as well as later discovered or invented naturally occurring or synthetic haptens, can be adapted for application in accordance with the invention.
The term “chemotherapeutic agent” means anti-cancer and other anti-hyperproliferative agents. Put simply, a “chemotherapeutic agent” refers to a chemical intended to destroy cells and tissues. Such agents include, but are not limited to: (1) DNA damaging agents and agents that inhibit DNA synthesis: e.g., anthracyclines (e.g., doxorubicin, donorubicin, epirubicin), alkylating agents (e.g., bendamustine, busulfan, carboplatin, carmustine, cisplatin, chlorambucil, cyclophosphamide, dacarbazine, hexamethylmelamine, ifosphamide, lomustine, mechlorethamine, melphalan, mitotane, mytomycin, pipobroman, procarbazine, streptozocin, thiotepa, and triethylenemelamine), platinum derivatives (e.g., cisplatin, carboplatin, cis diamminedichloroplatinum), telomerase and topoisomerase inhibitors (e.g., Camptosar), (2) tubulin-depolymerizing agents: e.g., taxoids (e.g., Paclitaxel, docetaxel, BAY 59-8862), (3) anti-metabolites such as capecitabine, chlorodeoxyadenosine, cytarabine (and its activated form, ara-CMP), cytosine arabinoside, dacabazine, floxuridine, fludarabine, 5-fluorouracil, 5-DFUR, gemcitibine, hydroxyurea, 6-mercaptopurine, methotrexate, pentostatin, trimetrexate, and 6-thioguanine (4) anti-angiogenics (e.g., Avastin, thalidomide, revlimid, sunitinib, lenalidomide), vascular disrupting agents (e.g., flavonoids/flavones, DMXAA, combretastatin derivatives such as CA4DP, ZD6126, AVE8062A, etc.), (5) biologics such as antibodies or antibody fragments (e.g., Herceptin, Avastin, Panorex, Rituxan, Zevalin, Mylotarg, Campath, Bexar, Erbitux, Lucentis), and (6) endocrine therapy: e.g., aromatase inhibitors (e.g., 4-hydroandrostendione, exemestane, aminoglutehimide, anastrozole, letozole), anti-estrogens (e.g., Tamoxifen, Toremifine, Raoxifene, Faslodex), steroids such as dexamethasone, (7) immuno-modulators: e.g., cytokines such as IFN-beta and IL2), inhibitors to integrins, other adhesion proteins and matrix metalloproteinases), (8) histone deacetylase inhibitors, (9) inhibitors of signal transduction such as inhibitors of tyrosine kinases like imatinib (Gleevec), (10) inhibitors of heat shock proteins, (11) retinoids such as all trans retinoic acid, (12) inhibitors of growth factor receptors or the growth factors themselves, (13) anti-mitotic compounds such as navelbine, Paclitaxel, taxotere, vinblastine, vincristine, vindesine, and vinorelbine, (14) anti-inflammatories such as COX inhibitors and (15) cell cycle regulators, e.g., check point regulators and telomerase inhibitors.
The term “sphingolipid” as used herein refers to the class of compounds in the art known as sphingolipids, including, but not limited to the following compounds (see http//www.lipidmaps.org as the site containing the links indicated by the bracketed alphanumeric strings below, which links contain chemical formulas, structural information, etc. for the corresponding compounds):
Sphingoid bases [SP01] Sphing-4-enines (Sphingosines) [SP0101] Sphinganines [SP0102] 4-Hydroxysphinganines (Phytosphingosines) [SP0103] Sphingoid base homologs and variants [SP0104] Sphingoid base 1-phosphates [SP0105] Lysosphingomyelins and lysoglycosphingolipids [SP0106] N-methylated sphingoid bases [SP0107] Sphingoid base analogs [SP0108]Ceramides [SP02] N-acylsphingosines (ceramides) [SP0201] N-acylsphinganines (dihydroceramides) [SP0202] N-acyl-4-hydroxysphinganines (phytoceramides) [SP0203] Acylceramides [SP0204] Ceramide 1-phosphates [SP0205]Phosphosphingolipids [SP03] Ceramide phosphocholines (sphingomyelins) [SP0301] Ceramide phosphoethanolamines [SP0302] Ceramide phosphoinositols [SP0303]Phosphonosphingolipids [SP04]Neutral glycosphingolipids [SP05] Simple Glc series (GlcCer, LacCer, etc) [SP0501] GalNAcb1-3Gala1-4Galb1-4Glc- (Globo series) [SP0502] GalNAcb1-4Galb1-4Glc- (Ganglio series) [SP0503] Galb1-3GlcNAcb1-3Galb1-4Glc- (Lacto series) [SP0504] Galb1-4GlcNAcb1-3Galb1-4Glc- (Neolacto series) [SP0505] GalNAcb1-3Gala1-3Galb1-4Glc- (Isoglobo series) [SP0506] GlcNAcb1-2Mana1-3Manb1-4Glc- (Mollu series) [SP0507] GalNAcb1-4GlcNAcb1-3Manb1-4Glc- (Arthro series) [SP0508] Gal- (Gala series) [SP0509] Other [SP0510]Acidic glycosphingolipids [SP06] Gangliosides [SP0601] Sulfoglycosphingolipids (sulfatides) [SP0602] Glucuronosphingolipids [SP0603] Phosphoglycosphingolipids [SP0604] Other [SP0600]Basic glycosphingolipids [SP07]Amphoteric glycosphingolipids [SP08]Arsenosphingolipids [SP09]
The present invention provides anti-sphingolipid S1P agents that are useful for treating or preventing hyperproliferative disorders such as cancer and cardiovascular or cerebrovascular diseases and disorders and various ocular disorders, as described in greater detail below. In particular the invention is drawn to S1P and its variants including but are not limited to sphingosine-1-phosphate [sphingene-1-phosphate; D-erythro-sphingosine-1-phosphate; sphing-4-enine-1-phosphate; (E,2S,3R)-2-amino-3-hydroxy-octadec-4-enoxy]phosphonic acid (AS 26993-30-6), DHS1P is defined as dihydrosphingosine-1-phosphate [sphinganine-1-phosphate; [(2S,3R)-2-amino-3-hydroxy-octadecoxy]phosphonic acid; D-Erythro-dihydro-D-sphingosine-1-phosphate (CAS 19794-97-9]; SPC is sphingosylphosphoryl choline, lysosphingomyelin, sphingosylphosphocholine, sphingosine phosphorylcholine, ethanaminium; 2-((((2-amino-3-hydroxy-4-octadecenyl) oxy)hydroxyphosphinyl)oxy)-N,N,N-trimethyl-, chloride, (R-(R*,S*-(E))), 2-[[(E,2R,3S)-2-amino-3-hydroxy-octadec-4-enoxy]-hydroxy-phosphoryl]oxyethy 1-trimethyl-azanium chloride (CAS 10216-23-6).
The term “epitope” or “antigenic determinant” when used herein, unless indicated otherwise, refers to the region of S1P to which an anti-S1P agent is reactive to.
The term “hyperproliferative disorder” refers to diseases and disorders associated with, the uncontrolled proliferation cells, including but not limited to uncontrolled growth of organ and tissue cells resulting in cancers or neoplasia and benign tumors. Hyperproliferative disorders associated with endothelial cells can result in diseases of angiogenesis such as angiomas, endometriosis, obesity, age-related macular degeneration and various retinopathies, as well as the proliferation of endothelial cells and smooth muscle cells that cause restenosis as a consequence of stenting in the treatment of atherosclerosis. Hyperproliferative disorders involving fibroblasts (for example, fibrogenesis) include but are not limited to disorders of excessive scarring (for example, fibrosis) such as age-related macular degeneration, cardiac remodeling and failure associated with myocardial infarction, excessive wound healing such as commonly occurs as a consequence of surgery or injury, keloids, and fibroid tumors and stenting.
The compositions of the invention are used in methods of sphingolipid-based therapy. “Therapy” refers to the prevention and/or treatment of diseases, disorders or physical trauma.
The term “sphingolipid metabolite” refers to a compound from which a sphingolipid is made, as well as a that results from the degradation of a particular sphingolipid. In other words, a “sphingolipid metabolite” is a compound that is involved in the sphingolipid metabolic pathways. Metabolites include metabolic precursors and metabolic products. The term “metabolic precursors” refers to compounds from which sphingolipids are made. Metabolic precursors of particular interest include but are not limited to SPC, sphingomyelin, dihydrosphingosine, dihydroceramide, and 3-ketosphinganine. The term “metabolic products” refers to compounds that result from the degradation of sphingolipids, such as phosphorylcholine (e.g., phosphocholine, choline phosphate), fatty acids, including free fatty acids, and hexadecanal (e.g., palmitaldehyde).
As used herein, the term “therapeutic” encompasses the fill spectrum of treatments for a disease or disorder. A “therapeutic” agent of the invention may act in a manner that is prophylactic or preventive, including those that incorporate procedures designed to target individuals that can be identified as being at risk (pharmacogenetics); or in a manner that is ameliorative or curative in nature; or may act to slow the rate or extent of the progression of at least one symptom of a disease or disorder being treated; or may act to minimize the time required, the occurrence or extent of any discomfort or pain, or physical limitations associated with recuperation from a disease, disorder or physical trauma; or may be used as an adjuvant to other therapies and treatments.
“Treatment” refers to both therapeutic treatment and prophylactic or preventative measures. Those in need of treatment include those already with the disorder as well as those in which the disorder is to be prevented.
The term “combination therapy” refers to a therapeutic regimen that involves the provision of at least two distinct therapies to achieve an indicated therapeutic effect. For example, a combination therapy may involve the administration of two or more chemically distinct active ingredients, for example, a fast-acting chemotherapeutic agent and an anti-lipid antibody. Alternatively, a combination therapy may involve the administration of an anti-lipid antibody and/or one or more chemotherapeutic agents, alone or together with the delivery of another treatment, such as radiation therapy and/or surgery. Further, a combination therapy may involve administration of an anti-lipid antibody together with one or more other biological agents (e.g., anti-VEGF, TGFβ, PDGF, or bFGF agent), chemotherapeutic agents and another treatment such as radiation and/or surgery. In the context of the administration of two or more chemically distinct active ingredients, it is understood that the active ingredients may be administered as part of the same composition or as different compositions. When administered as separate compositions, the compositions comprising the different active ingredients may be administered at the same or different times, by the same or different routes, using the same of different dosing regimens, all as the particular context requires and as determined by the attending physician. Similarly, when one or more anti-lipid antibody species, for example, an anti-S1P antibody, alone or in conjunction with one or more chemotherapeutic agents are combined with, for example, radiation and/or surgery, the drug(s) may be delivered before or after surgery or radiation treatment.
“Monotherapy” refers to a treatment regimen based on the delivery of one therapeutically effective compound, whether administered as a single dose or several doses over time.
“Neoplasia” or “cancer” refers to abnormal and uncontrolled cell growth. A “neoplasm”, or tumor or cancer, is an abnormal, unregulated, and disorganized proliferation of cell growth, and is generally referred to as cancer. A neoplasm may be benign or malignant. A neoplasm is malignant, or cancerous, if it has properties of destructive growth, invasiveness, and metastasis. Invasiveness refers to the local spread of a neoplasm by infiltration or destruction of surrounding tissue, typically breaking through the basal laminas that define the boundaries of the tissues, thereby often entering the body's circulatory system. Metastasis typically refers to the dissemination of tumor cells by lymphatics or blood vessels. Metastasis also refers to the migration of tumor cells by direct extension through serous cavities, or subarachnoid or other spaces. Through the process of metastasis, tumor cell migration to other areas of the body establishes neoplasms in areas away from the site of initial appearance.
“Mammal” for purposes of treatment refers to any animal classified as a mammal, including humans, domestic and farm animals, and zoo, sports, or pet animals, such as dogs, horses, cats, cows, etc. Preferably, the mammal is human.
“Native antibodies” and “native immunoglobulins” are usually heterotetrameric glycoproteins of about 150,000 Daltons, composed of two identical light (L) chains and two identical heavy (H) chains. Each light chain is linked to a heavy chain by one covalent disulfide bond, while the number of disulfide linkages varies among the heavy chains of different immunoglobulin isotypes. Each heavy and light chain also has regularly spaced intrachain disulfide bridges. Each heavy chain has at one end a variable domain (VH) followed by a number of constant domains. Each light chain has a variable domain at one end (VL) and a constant domain at its other end; the constant domain of the light chain is aligned with the first constant domain of the heavy chain, and the light-chain variable domain is aligned with the variable domain of the heavy chain. Particular amino acid residues are believed to form an interface between the light- and heavy-chain variable domains.
The term “variable” region comprises framework and CDRs (otherwise known as hypervariables) and refers to the fact that certain portions of the variable domains differ extensively in sequence among antibodies and are used in the binding and specificity of each particular antibody for its particular antigen. However, the variability is not evenly distributed throughout the variable domains of antibodies. It is concentrated in three segments called hypervariable regions both in the light chain and the heavy chain variable domains. The more highly conserved portions of variable domains are called the framework region (FR). The variable domains of native heavy and light chains each comprise four FRs (FR1, FR2, FR3 and FR4, respectively), largely adopting a β-sheet configuration, connected by three hypervariable regions, which form loops connecting, and in some cases forming part of, the β-sheet structure. The hypervariable regions in each chain are held together in close proximity by the FRs and, with the hypervariable regions from the other chain, contribute to the formation of the antigen-binding site of antibodies (see Kabat, et al., Sequences of Proteins of Immunological Interest, 5th Ed. Public Health Service, National Institutes of Health, Bethesda, Md. (1991), pages 647-669). The constant domains are not involved directly in binding an antibody to an antigen, but exhibit various effector functions, such as participation of the antibody in antibody-dependent cellular toxicity.
The term “hypervariable region” when used herein refers to the amino acid residues of an antibody which are responsible for antigen binding. The hypervariable region comprises amino acid residues from a “complementarity determining region” or “CDR” (for example, residues 24-34 (L1), 50-56 (L2), and 89-97 (L3) in the light chain variable domain and 31-35 (H1), 50-65 (H2), and 95-102 (H3) in the heavy chain variable domain; Kabat, et al. (1991), above) and/or those residues from a “hypervariable loop” (for example residues 26-32 (L1), 50-52 (L2), and 91-96 (L3) in the light chain variable domain and 26-32 (H1), 53-55 (H2), and 96-101 (H3) in the heavy chain variable domain; Chothia and Lesk J. Mol. Biol. 196:901-917 (1987)). “Framework” or “FR” residues are those variable domain residues other than the hypervariable region residues as herein defined.
Papain digestion of antibodies produces two identical antigen-binding fragments, called “Fab” fragments, each with a single antigen-binding site, and a residual “Fc” fragment, whose name reflects its ability to crystallize readily. Pepsin treatment yields an F(ab′)2 fragment that has two antigen-combining sites and is still capable of cross-linking antigen.
“Fv” is the minimum antibody fragment that contains a complete antigen-recognition and -binding site. This region consists of a dimer of one heavy chain and one light chain variable domain in tight, non-covalent association. It is in this configuration that the three hypervariable regions of each variable domain interact to define an antigen-binding site on the surface of the VH-VL dimer. Collectively, the six hypervariable regions confer antigen-binding specificity to the antibody. However, even a single variable domain (or half of an Fv comprising only three hypervariable regions specific for an antigen) has the ability to recognize and bind antigen, although at a lower affinity than the entire binding site.
The Fab fragment also contains the constant domain of the light chain and the first constant domain (CH1) of the heavy chain. Fab′ fragments differ from Fab fragments by the addition of a few residues at the carboxyl terminus of the heavy chain CH1 domain including one or more cysteine(s) from the antibody hinge region. Fab′-SH is the designation herein for Fab′ in which the cysteine residue(s) of the constant domains bear a free thiol group. F(ab′)2 antibody fragments originally were produced as pairs of Fab′ fragments which have hinge cysteines between them. Other chemical couplings of antibody fragments are also known.
The “light chains” of antibodies (immunoglobulins) from any vertebrate species can be assigned to one of two clearly distinct types, called kappa (κ) and lambda (λ), based on the amino acid sequences of their constant domains.
Depending on the amino acid sequence of the constant domain of their heavy chains, immunoglobulins can be assigned to different classes. Presently there are five major classes of immunoglobulins: IgA, IgD, IgE, IgG, and IgM, and several of these may be further divided into subclasses (isotypes), e.g., IgG1, IgG2, IgG3, IgG4, IgA, and IgA2. The heavy-chain constant domains that correspond to the different classes of immunoglobulins are called alpha, delta, epsilon, gamma, and mu, respectively. The subunit structures and three-dimensional configurations of different classes of immunoglobulins are well known.
The term “antibody” herein is used in the broadest sense and specifically covers monoclonal antibodies (including full length monoclonal antibodies), polyclonal antibodies, multispecific antibodies (e.g., bispecific antibodies), antibody fragments, and binding agents that employ the CDRs (or variant thereof that retain antigen binding activity) of the parent antibody. Antibodies are defined herein as retaining at least one desired activity of the parent antibody. Desired activities can include the ability to bind the antigen specifically, the ability to inhibit proleration in vitro, the ability to inhibit angiogenesis in vivo, and the ability to alter cytokine profile in vitro. “Antibody fragments” comprise a portion of a full-length antibody, generally the antigen binding or variable domain thereof. Examples of antibody fragments include Fab, Fab′, F(ab′)2, and Fv fragments; diabodies; linear antibodies; single-chain antibody molecules; and multispecific antibodies formed from antibody fragments.
The term “monoclonal antibody” as used herein refers to an antibody obtained from a population of substantially homogeneous antibodies, for example, the individual antibodies comprising the population are identical except for possible naturally occurring mutations that may be present in minor amounts. Monoclonal antibodies are highly specific, being directed against a single antigenic site. Furthermore, in contrast to conventional (polyclonal) antibody preparations that typically include different antibodies directed against different determinants (epitopes), each monoclonal antibody is directed against a single determinant on the antigen. The modifier “monoclonal” indicates the character of the antibody as being obtained from a substantially homogeneous population of antibodies, and is not to be construed as requiring production of the antibody by any particular method. For example, the monoclonal antibodies to be used in accordance with the present invention may be made by the hybridoma method first described by Kohler, et al., Nature 256:495 (1975), or may be made by recombinant DNA methods (see, e.g., U.S. Pat. No. 4,816,567). The “monoclonal antibodies” may also be isolated from phage antibody libraries using the techniques described in Clackson, et al., Nature 352:624-628 (1991) and Marks et al., J. Mol. Biol. 222:581-597 (1991), for example.
The monoclonal antibodies herein specifically include “chimeric” antibodies (immunoglobulins) in which a portion of the heavy and/or light chain is identical with or homologous to corresponding sequences in antibodies derived from a particular species or belonging to a particular antibody class or subclass, while the remainder of the chain(s) is identical with or homologous to corresponding sequences in antibodies derived from another species or belonging to another antibody class or subclass, as well as fragments of such antibodies, so long as they exhibit the desired biological activity (U.S. Pat. No. 4,816,567; and Morrison, et al., Proc. Natl. Acad. Sci. USA 81:6851-6855 (1984)).
“Humanized” forms of non-human (e.g., murine) antibodies are chimeric antibodies that contain minimal sequence derived from non-human immunoglobulin. For the most part, humanized antibodies are human immunoglobulins (recipient antibody) in which hypervariable region residues of the recipient are replaced by hypervariable region residues from a non-human species (donor antibody) such as mouse, rat, rabbit or nonhuman primate having the desired specificity, affinity, and capacity. In some instances, framework region (FR) residues of the human immunoglobulin are replaced by corresponding non-human residues. Furthermore, humanized antibodies may comprise residues that are not found in the recipient antibody or in the donor antibody. These modifications are made to further refine antibody performance. In general, the humanized antibody will comprise substantially all of at least one, and typically two, variable domains, in which all or substantially all of the hypervariable regions correspond to those of a non-human immunoglobulin and all or substantially all of the FRs are those of a human immunoglobulin sequence. The humanized antibody optionally also will comprise at least a portion of an immunoglobulin constant region (Fc), typically that of a human immunoglobulin. For further details, see Jones, et al., Nature 321:522-525 (1986); Reichmann, et al., Nature 332:323-329 (1988); and Presta, Curr. Op. Struct. Biol. 2:593-596 (1992) and Hansen, WO2006105062.
“Single-chain Fv” or “sFv” antibody fragments comprise the VH and VL domains of antibody, wherein these domains are present in a single polypeptide chain. Generally, the Fv polypeptide further comprises a polypeptide linker between the VH and VL domains that enables the sFv to form the desired structure for antigen binding. For a review of sFv, see Pluckthun in The Pharmacology of Monoclonal Antibodies, vol. 113, Rosenburg and Moore eds. Springer-Verlag, New York, pp. 269-315 (1994).
The term “diabodies” refers to small antibody fragments with two antigen-binding sites, which fragments comprise a heavy chain variable domain (VH) connected to a light chain variable domain (VL) in the same polypeptide chain (VH-VL). By using a linker that is too short to allow pairing between the two domains on the same chain, the domains are forced to pair with the complementary domains of another chain and create two antigen-binding sites. Diabodies are described more fully in, for example, EP 404,097; WO 93/11161; and Hollinger, et al., Proc. Natl. Acad. Sci. USA 90:6444-6448 (1993).
The expression “linear antibodies” when used throughout this application refers to the antibodies described in Zapata, et al. Protein Eng. 8(10):1057-1062 (1995). Briefly, these antibodies comprise a pair of tandem Fd segments (VH-CH1-V H-CH1) that form a pair of antigen binding regions. Linear antibodies can be bispecific or monospecific.
A “variant” anti-sphingolipid antibody, refers herein to a molecule which differs in amino acid sequence from a “parent” anti-sphingolipid antibody amino acid sequence by virtue of addition, deletion, and/or substitution of one or more amino acid residue(s) in the parent antibody sequence and retains at least one desired activity of the parent anti-binding antibody. Desired activities can include the ability to bind the antigen specifically, the ability to inhibit proleration in vitro, the ability to inhibit angiogenesis in vivo, and the ability to alter cytokine profile in vitro. In one embodiment, the variant comprises one or more amino acid substitution(s) in one or more hypervariable region(s) of the parent antibody. For example, the variant may comprise at least one, e.g. from about one to about ten, and preferably from about two to about five, substitutions in one or more hypervariable regions of the parent antibody. Ordinarily, the variant will have an amino acid sequence having at least 50% amino acid sequence identity with the parent antibody heavy or light chain variable domain sequences, more preferably at least 65%, more preferably at least 75%, more preferably at least 80%, more preferably at least 85%, more preferably at least 90%, and most preferably at least 95% sequence identity. Identity or homology with respect to this sequence is defined herein as the percentage of amino acid residues in the candidate sequence that are identical with the parent antibody residues, after aligning the sequences and introducing gaps, if necessary, to achieve the maximum percent sequence identity. None of N-terminal, C-terminal, or internal extensions, deletions, or insertions into the antibody sequence shall be construed as affecting sequence identity or homology. The variant retains the ability to bind a sphingolipid and preferably has desired activities which are superior to those of the parent antibody. For example, the variant may have a stronger binding affinity, enhanced ability to reduce angiogenesis and/or halt tumor progression. To analyze such desired properties (for example less immunogenic, longer half-life, enhanced stability, enhanced potency), one should compare a Fab form of the variant to a Fab form of the parent antibody or a full length form of the variant to a full length form of the parent antibody, for example, since it has been found that the format of the anti-sphingolipid antibody impacts its activity in the biological activity assays disclosed herein. The variant antibody of particular interest herein can be one which displays at least about 5%, preferably at least about 10%, 25%, 59%, or more of at least one desired activity. The preferred variant is one that has superior biophysical properties as measured in vitro or superior activities biological as measured in vitro or in vivo when compared to the parent antibody.
The “parent” antibody herein is one that is encoded by an amino acid sequence used for the preparation of the variant. Preferably, the parent antibody has a human framework region and, if present, has human antibody constant region(s). For example, the parent antibody may be a humanized or human antibody.
An “isolated” antibody is one that has been identified and separated and/or recovered from a component of its natural environment. Contaminant components of its natural environment are materials that would interfere with diagnostic or therapeutic uses for the antibody, and may include enzymes, hormones, and other proteinaceous or nonproteinaceous solutes. In preferred embodiments, the antibody will be purified (1) to greater than 95% by weight of antibody as determined by the Lowry method, and most preferably more than 99% by weight, (2) to a degree sufficient to obtain at least 15 residues of N-terminal or internal amino acid sequence by use of a spinning cup sequenator, or (3) to homogeneity by SDS-PAGE under reducing or nonreducing conditions using Coomassie blue or, preferably, silver stain. Isolated antibody includes the antibody in situ within recombinant cells since at least one component of the antibody's natural environment will not be present. Ordinarily, however, isolated antibody will be prepared by at least one purification step.
The word “label” when used herein refers to a detectable compound or composition that is conjugated directly or indirectly to the antibody. The label may itself be detectable by itself (e.g., radioisotope labels or fluorescent labels) or, in the case of an enzymatic label, may catalyze chemical alteration of a substrate compound or composition that is detectable.
“Neuropathic pain” is a chronic pain state caused by pathologic changes in the nervous system.
A “patentable” composition, process, machine, or article of manufacture according to the invention means that the subject matter satisfies all statutory requirements for patentability at the time the analysis is performed. For example, with regard to novelty, non-obviousness, or the like, if later investigation reveals that one or more claims encompass one or more embodiments that would negate novelty, non-obviousness, etc., the claim(s), being limited by definition to “patentable” embodiments, specifically exclude the unpatentable embodiment(s). Also, the claims appended hereto are to be interpreted both to provide the broadest reasonable scope, as well as to preserve their validity. Furthermore, the claims are to be interpreted in a way that (1) preserves their validity and (2) provides the broadest reasonable interpretation under the circumstances, if one or more of the statutory requirements for patentability are amended or if the standards change for assessing whether a particular statutory requirement for patentability is satisfied from the time this application is filed or issues as a patent to a time the validity of one or more of the appended claims is questioned.
The term “pharmaceutically acceptable salt” refers to salts which retain the biological effectiveness and properties of the agents and compounds of this invention and which are not biologically or otherwise undesirable. In many cases, the agents and compounds of this invention are capable of forming acid and/or base salts by virtue of the presence of charged groups, for example, charged amino and/or carboxyl groups or groups similar thereto. Pharmaceutically acceptable acid addition salts may be prepared from inorganic and organic acids, while pharmaceutically acceptable base addition salts can be prepared from inorganic and organic bases. For a review of pharmaceutically acceptable salts (see Berge, et al. (1977) J. Pharm. Sci., vol. 66, 1-19).
A “plurality” means more than one.
The terms “separated”, “purified”, “isolated”, and the like mean that one or more components of a sample contained in a sample-holding vessel are or have been physically removed from, or diluted in the presence of, one or more other sample components present in the vessel. Sample components that may be removed or diluted during a separating or purifying step include, chemical reaction products, unreacted chemicals, proteins, carbohydrates, lipids, and unbound molecules.
The term “species” is used herein in various contexts, e.g., a particular species of drug. In each context, the term refers to a population of chemically indistinct molecules of the sort referred in the particular context.
“Specifically associate” and “specific association” and the like refer to a specific, non-random interaction between two molecules, which interaction depends on the presence of structural, hydrophobic/hydrophilic, and/or electrostatic features that allow appropriate chemical or molecular interactions between the molecules.
A “subject” or “patient” refers to an animal in need of treatment that can be effected by molecules of the invention. Animals that can be treated in accordance with the invention include vertebrates, with mammals such as bovine, canine, equine, feline, ovine, porcine, and primate (including humans and non-human primates) animals being particularly preferred examples.
A “therapeutically effective amount” (or “effective amount”) refers to an amount of an active ingredient, e.g., an agent according to the invention, sufficient to effect treatment when administered to a subject or patient. Accordingly, what constitutes a therapeutically effective amount of a composition according to the invention may be readily determined by one of ordinary skill in the art. In the context of ocular therapy, a “therapeutically effective amount” is one that produces an objectively measured change in one or more parameters associated with treatment of the ocular disease or condition including an increase or decrease in the expression of one or more genes correlated with the ocular disease or condition, induction of apoptosis or other cell death pathways, clinical improvement in symptoms, a decrease in aberrant neovascularization or in inflammation, etc. Of course, the therapeutically effective amount will vary depending upon the particular subject and condition being treated, the weight and age of the subject, the severity of the disease condition, the particular compound chosen, the dosing regimen to be followed, timing of administration, the manner of administration and the like, all of which can readily be determined by one of ordinary skill in the art. It will be appreciated that in the context of combination therapy, what constitutes a therapeutically effective amount of a particular active ingredient may differ from what constitutes a therapeutically effective amount of the active ingredient when administered as a monotherapy (ie., a therapeutic regimen that employs only one chemical entity as the active ingredient).
The term “treatment” or “treating” of a disease or disorder includes preventing or protecting against the disease or disorder (that is, causing the clinical symptoms not to develop); inhibiting the disease or disorder (i.e., arresting or suppressing the development of clinical symptoms; and/or relieving the disease or disorder (i.e., causing the regression of clinical symptoms). As will be appreciated, it is not always possible to distinguish between “preventing” and “suppressing” a disease or disorder since the ultimate inductive event or events may be unknown or latent. Accordingly, the term “prophylaxis” will be understood to constitute a type of “treatment” that encompasses both “preventing” and “suppressing.” The term “treatment” thus includes “prophylaxis”.
The term “therapeutic regimen” means any treatment of a disease or disorder using chemotherapeutic drugs, radiation therapy, surgery, gene therapy, DNA vaccines and therapy, antisense-based therapies including siRNA therapy, anti-angiogenic therapy, immunotherapy, bone marrow transplants, aptamers and other biologics such as antibodies and antibody variants, receptor decoys and other protein-based therapeutics.